Zeolitic imidazolate framework

The structure of a zeolitic imidazolate framework is made through three-dimensional assembly of metal(imidazolate)4 tetrahedra.

Zeolitic imidazolate frameworks (ZIFs) are a class of metal-organic frameworks (MOFs) that are topologically isomorphic with zeolites. ZIFs are composed of tetrahedrally-coordinated transition metal ions (e.g. Fe, Co, Zn) connected by imidazolate linkers. Since the metal-imidazole-metal angle is similar to the 145° Si-O-Si angle in zeolites, ZIFs have zeolite-like topologies. As of 2010, 105 ZIF topologies have been reported in the literature. Due to their robust porosity, resistance to thermal changes, and chemical stability, ZIFs are being investigated for applications such as carbon dioxide capture.

ZIF glasses can be synthesized by the melt-quench method, and the first melt-quenched ZIF glass was firstly made and reported by Bennett et al. back in 2015. ZIFs remain porous even after forming glasses, recent studies have revealed that the linker modification can really modulate the melting behaviour of ZIFs. ZIF glasses are a newly discovered type of material that has been garnering increasing interest in recent years, with around 13 different ZIFs, including ZIF-4, ZIF-62, and ZIF-76, being successfully prepared in their glassy state. In traditional materials science, glasses can be divided into three major families: inorganic, organic, and metallic. The chemical bonds that make up the structure of members of each family are mixed ionic/covalent bonds, covalent bonds, and metallic bonds, respectively. ZIF glasses, on the other hand, are an organic-inorganic coordinated glass discovered only recently, and have a completely different structure than the three traditional glass families. They thus represent a fourth type of glass.